Observation Date: 02/24/2013
We ascended from the Bear Creek overlook road to the ridge above “south bowl”. We conferred and did some snow analysis on the north-east facing edge of the bowl. Our elevation was around 8300.
The weather was for the most part completely overcast, but at times broke with brief sun and at other times visibility became partially obscured on the ridge. There was snow in the air, but it was primarily wind transported Temperature was 19 degrees.
Wind speed was 10-15 south east with stronger gusts at the ridge. Most of the snow was being transported rather than falling fresh.
New Snow: 6-12″
Snow DensityThe mass of snow per unit volume, but often expressed as a percent water content. New fallen powder has a low densityThe mass of snow per unit volume, but often expressed as a percent water content. New fallen powder has a low density (3-10%), while heavy or wet snow is more dense (10-20%). (3-10%), while heavy or wet snow is more dense (10-20%).:
We did not observe any recent avalanche activity. There was a lot of wind transport happening during our tour and evidence of sustained wind activity. The cornices just keep getting bigger and bigger! Our party dug two pits which exhibited striking examples of spatial variability. Doug’s pit was about 25 meters further up the ridge from ours and exhibited much different, more stable results.
Our pit was at about 8200 ft, n/ne aspectThe compass direction a slope faces i.e. North, South, East, West., 185 cm snowpack depth. The pit was on a 25 degree convexity above a 39 degree (average) slope. Our column tests showed layers of concern at 10cm (new/transport-fist), 25cm (four finger), and 80-90cm (one finger) down from the surface. Once the upper 10 cm of new snow cleared we had consistent failures of the top 25 cm at CT 4 Q2 with the deeper 85ish layer going at CT 12-15 Q1-2.
Our extended column test had the most dramatic results with an ECTP 1 Q2 at 20 cm. This was followed by a ECTX 14 Q3 at 60 cm and an exciting ECTP 15 Q1 at 75 cm down from the surface. The 5 cm snow above the deepest layer of concern exhibited large decomposing faceted grains.
Although there were some safe route options into south bowl we chose to ski some stellar Bitterroot Butter below the overlook.
Observed Danger Rating:
We are curious if the deep unstable layer we observed is the same layer we’ve been seeing all year. If so this layer has been awful persistent.
Observer: Caleb Kasper